Fix mmctl download bash script (#20014)

There are cases that instead of suffix, we get a SHA prefix for cherrypicking branch
We rewrite the regex to support this case

scripts/download_mmctl_release.sh

@@ -19,7 +19,7 @@ BIN_PATH=${2:-bin}
 THIS_BRANCH=$(git rev-parse --abbrev-ref HEAD)
 if [[ "$THIS_BRANCH" =~ 'release-'[0-9] ]];
 then
-  RELEASE_TO_DOWNLOAD=$(echo $THIS_BRANCH | grep -Eo 'release-.*')
+  RELEASE_TO_DOWNLOAD=$(echo $THIS_BRANCH | grep -Eo 'release-([0-9](\.){0,1})\.([0-9](\.){0,1})')
 else
   RELEASE_TO_DOWNLOAD=master
 fi